How to create smooth surface (skin) for a model made of beams?
I think your best way forward is to either contact the producer of that model (they may have a version with smooth skin rather than the cubes and beams) or to reproduce a similar model and pose using a model created with a tool such as MakeHuman  or the Manuel Bastioni Lab add-on (although that looks to have been discontinued... however, there's a community supported branch available at https://github.com/animate1978/MB-Lab/wiki).